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Surface Plasmon Resonances of Metal Colloidal Particles Synthesized by a Photo-Chemical Process
Surface Plasmon Resonances of Metal Colloidal Particles Synthesized by a Photo-Chemical Process
Journal of the Korean Chemical Society. 1999. Feb, 43(1): 1-7
  • Published : February 00, 1999
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Ko, Min-Jin
Plawsky, Joel

Abstract
Metal colloidal particles have been prepared by a photo-chemical process in an aqueous solution containing semiconductor nanocrystallites. Metal colloidal particles produced in CdS and AgBr exhibit different absorption spectra. Au particles produced in solution with CdS show typical Au plasmon resonance absorption spectra. On the other hand Ag particles in solution with AgBr shows surface plasmon resonance absorption spectra which are red-shifted, as compared to that of a dispersion of homogeneous Ag colloidal particles in the same host. The extent of red-shift depends on the UV illumination time. This phenomenon is interpreted within the context of effective medium theory for small volume fractions. From the theory, a metal coated particle predicts Ag plasmon resonance, red shifted with respect to 400 nm that would be associated with a silver particle in solution. The absorption peak position is very sensitive to the coating thickness.